Air conditioner

ABSTRACT

An air conditioner is provided. The air conditioner may include a compressor that compresses a refrigerant, an outdoor heat-exchanger that heat-exchanges with the refrigerant discharged from the compressor according to a first operation mode, an indoor heat-exchanger that heat-exchanges with the refrigerant discharged from the compressor according to a second operation mode, and an expander that decompresses the refrigerant passing through the outdoor heat-exchanger or the indoor heat-exchanger. The expander may include a first decompression portion disposed at an outlet side or an inlet side of the outdoor heat-exchanger, the first decompression portion having a first inner diameter, and a second decompression portion connected to the first decompression portion in series, the second decompression portion having a second inner diameter greater than the first inner diameter.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority under 35 U.S.C. 119 and 35U.S.C. 365 to Korean Patent Application No. 10-2011-0032179, filed inKorea on Apr. 7, 2011, which is hereby incorporated by reference in itsentirety.

BACKGROUND

1. Field

An air conditioner is disclosed herein.

2. Background

Air conditioners are known. However, they suffer from variousdisadvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the followingdrawings in which like reference numerals refer to like elements, andwherein:

FIG. 1 is a schematic diagram of an air conditioner according to anembodiment;

FIG. 2 is a perspective view of the expander of FIG. 1;

FIG. 3 is a side view of a portion of the expander of FIG. 2;

FIG. 4 is a graph illustrating a difference in flow rate of arefrigerant in cooling and heating operations according to anembodiment; and

FIG. 5 is a view illustrating a portion of an expander according toanother embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described with reference to theaccompanying drawings. The concepts may, however, be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein; rather, alternate embodiments included inother retrogressive inventions or falling within the spirit and scope ofthe present disclosure may fully convey the concepts to those skilled inthe art.

Generally, air conditioners are home appliances that maintain indoor airat a proper state according to a use and purpose thereof. For example,such an air conditioner may cool indoor air in summer and warm theindoor air in winter. Further, the air conditioner may control ahumidity of the indoor air and purify the indoor air by removingimpurities therefrom. As products for life's convenience, such as airconditioners, are gradually expanded in use, consumers require productshaving high energy efficiency, superior performance, and greaterconvenience in use.

The air conditioner may perform a cooling or heating operation for anindoor space according to an operation direction of a refrigerationcycle. That is, a flow direction of a refrigerant flowing in therefrigeration cycle may vary according to a specific operation condition(cooling or heating requirement). Further, the cooling or heatingoperation may be selectively performed using one system device.

In more detail, the refrigeration cycle may be formed by sequentiallyconnecting to each other a compressor, an outdoor heat-exchanger, anexpander, and an indoor heat-exchanger. When a cooling operation isperformed, the refrigerant passing through the compressor may becondensed in the outdoor heat-exchanger and expanded (decompressed)while passing through the expander. Then, the refrigerant may beevaporated in the indoor heat-exchanger and introduced again into thecompressor. On the other hand, when a heating operation is performed,the refrigerant passing through the compressor may be condensed in theindoor heat-exchanger and passes through the expander. Then, therefrigerant may be evaporated in the outdoor heat-exchanger andintroduced again into the compressor.

The refrigerant passing through the outdoor heat-exchanger or the indoorheat-exchanger may be additionally condensed in a liquid state to reachan overcooled state. As the overcooled degree of the refrigerantincreases, a flow rate of the refrigerant passing through the expandermay increase. Thus, the flow rate of the refrigerant may increase toimprove the cooling or heating performance.

An expander is a device that controls the flow rate of the refrigerantand a pressure of the system. Thus, the expander may act as an importantelement for determining the cooling or heating performance. Typically,the expander may have a constant sectional area (constant innerdiameter).

According to pressure and temperature (outdoor temperature and indoortemperature) of the refrigeration cycle, an overcooled degree of therefrigerant during the heating operation may be higher than that of therefrigerant during the cooling operation. Thus, a flow rate of therefrigerant during the heating operation may be greater than that of therefrigerant during the cooling operation.

However, when a flow rate of the refrigerant during the heatingoperation is less than that of the refrigerant during the coolingoperation, it may be difficult to obtain a flow rate of the refrigerantfor the cooling or heating operation required in the refrigerationsystem. For example, the refrigerant may have a flow rate greater thanthat required during the heating operation, and also, the refrigerantmay have a flow rate less than that required during the coolingoperation.

As a result, refrigeration performance during the cooling operation maybe insufficient, and the refrigerant performance during the heatingoperation may be excessive.

FIG. 1 is a schematic diagram of an air conditioner according to anembodiment. Referring to FIG. 1, the air conditioner 1 may include acompressor 10 that compresses a refrigerant to a high-temperature andhigh-pressure, an outdoor heat-exchanger 30 disposed in an outdoor spacethat heat-exchanges the refrigerant with outdoor air, an indoorheat-exchanger 40 disposed in an indoor space that heat-exchanges therefrigerant with indoor air, and an expander 100 that decompresses therefrigerant condensed in the outdoor heat-exchanger 30 or the indoorheat-exchanger 40 to a predetermined pressure.

The air conditioner 1 may further include a flow converter 20 thatguides the refrigerant discharged from the compressor 10 toward theoutdoor heat-exchanger 30 or the indoor heat-exchanger 40. The flowconverter 20 may include a four-way valve that controls a flow directionof the refrigerant.

When a cooling operation is performed, the refrigerant discharged fromthe compressor 10 may pass through the flow converter 20 to flow towardthe outdoor heat-exchanger 30. On the other hand, when a heatingoperation is performed, the refrigerant discharged from the compressor10 may pass through the flow converter 20 to flow toward the indoorheat-exchanger 40.

A gas/liquid separator 50 that filters a liquid refrigerant from anevaporated refrigerant may be disposed at an inlet side of thecompressor 10. A gaseous refrigerant passing through the gas/liquidseparator 50 may be introduced into the compressor 10.

The expander 100 may include a first capillary tube 110 disposed at anoutlet or inlet side of the outdoor heat-exchanger 30 and a secondcapillary tube 150 disposed at an outlet or inlet side of the indoorheat-exchanger 40. The first capillary tube 110 may be referred to as a“first decompression portion”, and the second capillary tube 150 may bereferred to as a “second decompression portion”. The term “outlet side”and “inlet side” may be understood as terms defined on the basis of theflow direction of the refrigerant.

The first and second capillary tubes 110 and 150 may be connected toeach other in series. Also, the first and second capillary tubes 110 and150 may have diameters different from each other. The refrigerant may bephase-converted from an overcooled liquid state into a two-phase state(i.e., a mixed state of liquid and gaseous refrigerants) while passingthrough the expander 100.

A flow direction of the refrigerant according to an operation mode willbe described hereinbelow.

When the air conditioner 1 is operated in a cooling operation mode (afirst operation mode), the refrigerant may flow in a direction (A),shown in FIG. 1 as a solid arrow. In more detail, the refrigerantpassing through the compressor 10 may pass through the flow converter 20and be introduced into the outdoor heat-exchanger 30. Then, therefrigerant may be condensed while passing through the outdoorheat-exchanger 30. When the condensation of the refrigerant iscompleted, the refrigerant may be converted into an overcooled liquidstate.

The refrigerant in the overcooled liquid state may be decompressed to apredetermined pressure while passing through the expander 100, and thus,a flow rate of the refrigerant may be controlled. That is, the flow rateof the refrigerant may be controlled according to structuralcharacteristics of the expander 100, for example, an inner diameter orlength of the expander 100.

The refrigerant passing through the expander 100 may be evaporated whilepassing through the indoor heat-exchanger 40. Then, the evaporatedrefrigerant may pass through the gas/liquid separator 50 via the flowconverter 20, and the gaseous liquid, from which the liquid refrigerantis separated, may be introduced into the compressor 10. The refrigerantcirculation process may be repeatedly performed.

On the other hand, when the air conditioner 1 is operated in a heatingmode (a second operation mode), the refrigerant may flow in a direction(B), shown in FIG. 1 as a dotted arrow. In more detail, the refrigerantpassing through the compressor 10 may pass through the flow converter 20and be introduced into the indoor heat-exchanger 40. Then, therefrigerant may be condensed while passing through the indoorheat-exchanger 40. When the condensation of the refrigerant iscompleted, the refrigerant may be converted into an overcooled liquidstate.

The refrigerant in the overcooled liquid state may be decompressed to apredetermined pressure while passing through the expander 100, and thus,a flow rate of the refrigerant may be controlled. Also, the refrigerantpassing through the expander 100 may be evaporated while passing throughthe outdoor heat-exchanger 30, and the evaporated refrigerant may beintroduced into the compressor 10 through the flow converter 20 and thegas/liquid separator 50. The refrigerant circulation process may berepeatedly performed.

As described above, when the cooling or heating operation is performed,the refrigerant circulating through the refrigeration cycle may bechanged in flow direction. In more detail, when the cooling operation isperformed, the refrigerant condensed in the outdoor heat-exchanger 30may successively pass through the first capillary tube 110 and thesecond capillary tube 150 and may be introduced into the indoor heatexchanger 40. That is, the first capillary tube 110 may be disposed atan outlet side of the outdoor heat-exchanger 30, and the secondcapillary tube 150 may be disposed at an inlet side of the indoorheat-exchanger 40.

On the other hand, when the heating operation is performed, therefrigerant condensed in the indoor heat-exchanger 40 may successivelypass through the second capillary tube 150 and the first capillary tube110 and be introduced into the outdoor heat-exchanger 30. That is, thesecond capillary tube may be disposed at an outlet side of the indoorheat-exchanger 40, and the first capillary tube 110 may be disposed atthe inlet side of the outdoor heat-exchanger 30.

When the first and the second capillary tubes 110 and 150 have innerdiameters different from each other, a flow resistance of therefrigerant flowing into the first or second capillary tube 110 or 150may be different. Thus, pressure drop or refrigerant flow rate may bedifferent. More specifically, when an inner diameter of the capillarytube decreases, the pressure drop may increase and the refrigerant flowrate may decrease. Hereinafter, expander 100 will be described in detailwith reference to the accompanying drawings.

FIG. 2 is a perspective view of the expander FIG. 1. FIG. 3 is a sideview of a portion of the expander of FIG. 2. Referring to FIGS. 2 and 3,the expander 100 may include the plurality of capillary tubes 110 and150, which may be connected to each other in series.

The plurality of capillary tubes 110 and 150 may include the firstcapillary tube 110, which may be connected to an outlet side of theoutdoor heat-exchanger 30 during the cooling operation, and the secondcapillary tube 150, which may be connected to an outlet side of theindoor heat-exchanger 40 during the heating operation. Each of the firstand second capillary tubes 110 and 150 may be wound in a coil shape, andmay be coupled to each other.

The first capillary tube 110 may include a cooling refrigerant inflowportion 111, through which the refrigerant discharged from the outdoorheat-exchanger 30 may be introduced, and a first coupling portion 112coupled to the second capillary tube 150. The cooling refrigerant inflowpart 111 may be disposed on an end of one side of the first capillarytube 110, and the first coupling part 112 may be disposed on an end ofthe other side of the first capillary tube 110.

In the cooling operation mode, the refrigerant passing through theoutdoor heat-exchanger 30 may be introduced into the expander 100through the cooling refrigerant inflow portion 111. On the other hand,in the heating operation mode, the refrigerant passing through thesecond capillary tube 150 and the first capillary tube 110 may bedischarged from the expander 100 through the cooling refrigerant inflowportion 111.

The second capillary tube 150 may include a heating refrigerant inflowportion 151, through which the refrigerant discharged from the indoorheat-exchanger 40 may be introduced, and a second coupling portion 152coupled to the first capillary tube 150. The heating refrigerant inflowportion 151 may be disposed on an end of one side of the secondcapillary tube 150, and the second coupling part 152 may be disposed onan end of the other side of the second capillary tube 150.

In the heating operation mode, the refrigerant passing through theindoor heat-exchanger 40 may be introduced into the expander 100 throughthe heating refrigerant inflow portion 151. On the other hand, in thecooling operation mode, the refrigerant passing through the first andsecond capillary tubes 110 and 150 may be discharged from the expanderthrough the heating refrigerant inflow portion 151.

The first coupling portion 112 may be connected to the second couplingportion 152. For example, an end of the first capillary tube 110 may becoupled to an end of the second capillary tube 150.

The expander 100 may include a connection portion 130 coupled to thefirst and second coupling portions 112 and 152. The first and secondcapillary tubes 110 and 150 may communicate with each other through theconnection portion 130. That is, the refrigerant flowing into the firstcapillary tube 110 may be introduced into the second capillary tube 150through the connection portion 130, and the refrigerant flowing into thesecond capillary tube 150 may be introduced into the first capillarytube 110 through the connection portion 130.

The first and second coupling portions 112 and 152 may be, for example,welded to each other or coupled to each other through a separatecoupling member to manufacture the connection portion 130.Alternatively, the first coupling portion 112 may be inserted into thesecond coupling portion 152 to manufacture the connection portion 130.However, embodiments are not limited to such methods of manufacturingthe connection portion 130.

The cooling refrigerant inflow portion 111 may be an inlet port, throughwhich the refrigerant may be introduced into the expander 100 when thecooling operation is performed, and the heating refrigerant inflowportion 115 may be an inlet port, through which the refrigerant isintroduced into the expander 100 when the heating operation isperformed. On the other hand, the heating refrigerant inflow portion 115may be an outlet port, through which the refrigerant may be dischargedfrom the expander 110 when the cooling operation is performed, and thecooling refrigerant inflow part 111 may be an outlet port, through whichthe refrigerant may be discharged from the expander 110 when the heatingoperation is performed.

An inner diameter of the first capillary tube 110 may be referred tousing reference symbol D1 (a first inner diameter), and an innerdiameter of the second capillary tube 150 may be referred to usingreference symbol D2 (a second inner diameter). The second inner diameterD2 may be greater than the first inner diameter D1.

When the air conditioner 1 performs the cooling operation, the firstcapillary tube 110 may be referred to as an “expander” that provides aflow resistance, so that the refrigerant in the overcooled liquid stateis phase-changed into refrigerant having a liquid state. The secondcapillary tube 150 may be referred to as an “expander” that provides aflow resistance, so that the refrigerant in the liquid state isphase-changed into refrigerant having a two-phase state (i.e., a mixedstate of liquid and gaseous refrigerants). In this case, the firstcapillary tube 110 may be the expander in which a single phase flow isperformed, and the second capillary tube 150 may be the expander inwhich a two-phase flow (liquid phase and gaseous phase flow) isperformed.

On the other hand, when the air conditioner 1 performs the heatingoperation, the second capillary tube 150 may be referred to as an“expander” that provides a flow resistance, so that the refrigerant inthe overcooled liquid state is phase-changed into refrigerant in aliquid state. Also, the first capillary tube 110 may be referred to asan “expander” that provides a flow resistance, so that the refrigerantin the liquid state is phase-changed into refrigerant in the two-phasestate (the mixed state of the liquid and gaseous refrigerants). In thiscase, the second capillary tube 150 may be the expander in which asingle phase flow is performed, and the first capillary tube 110 may bethe expander in which a two-phase flow (liquid phase and gaseous phaseflow) is performed.

When the cooling operation is performed, the refrigerant maysuccessively pass through the first and second capillary tubes 110 and150 to form the single phase flow and the two-phase flow. During thesingle phase flow and the two-phase flow, a pressure drop due tofriction may occur within the first and second capillary tube 110 and150.

Further, when the refrigerant flows in the two-phase state, a pressuredrop due to acceleration of the refrigerant, in addition to the pressuredrop due to the friction within the capillary tube, may occur. Thus,when the refrigerant flows in the two-phase state, the pressure drop(flow resistance) effect may be significant when compared to that of thesingle phase flow. Also, when the pressure drop effect is significant, amass flow rate within the capillary tube may be relatively low.

The more the inner diameter of each of the first and second capillarytubes 110 and 150 decreases, the more the flow resistance increases.Thus, a flow rate of the refrigerant may decrease.

When the inner diameter of the capillary tube in which the two-phaseflow is performed decreases, the pressure drop effect of the refrigerantflowing into the expander 100 may increase. Thus, the flow rate of therefrigerant may decrease.

Referring to FIGS. 2 and 3, in the cooling operation mode (see arrow(A)), the refrigerant may flow into the first capillary tube 110 in thesingle phase state and flow into the second capillary tube 150 having aninner diameter greater than that of the first capillary tube 110 in thetwo-phase state. In the heating operation mode (see arrow (B)), therefrigerant may flow into the second capillary tube 150 in the singlephase state and flow into the first capillary tube 110 having an innerdiameter less than that of the second capillary tube 150 in thetwo-phase state.

Thus, since a refrigerant decompression effect in the heating operationmode is greater than that in the cooling operation mode, the flow rateof the refrigerant flowing into the expander 100 during the heatingoperation may be less than the refrigerant flowing into the expander 100during the cooling operation.

In summary, the plurality of capillary tubes 110 and 150 may beconnected to each other in series, and the refrigerant may pass throughthe plurality of capillary tubes 110 and 150 during the cooling orheating operation. However, because the plurality of capillary tubes 110and 150 have inner diameters different from each other, the cooling flowrate may be greater than the heating flow rate. In general, consideringthat the refrigerant flow rate required for the heating operation may beless than that required for the cooling operation, the refrigerant flowrate required for the system during the cooling and heating operationmay be satisfied by the above-described configuration.

Hereinafter, a refrigerant decompression effect due to a length of thefirst or second capillary tube 110 or 150 will be described withreference to Table. 1.

TABLE 1 First capillary Second capillary Classification tube (110) tube(150) Length L of L1 L2 capillary tube

In general, when the capillary tube increases in length, a decompressioneffect of the refrigerant passing through the inside of the capillarytube may increase. Thus, the more the length L1 of the first capillarytube 110 or the length L2 of the second capillary tube 150 increases,the more the refrigerant decompression performance may increase and therefrigerant flow rate may relatively decrease. The lengths L1 and L2 maybe set to specific values according to the phase-change process of therefrigerant during the cooling or heating operation.

That is, the length L1 may be set so that the refrigerant flows into thefirst capillary tube 110 in the single phase state and then flows intothe second capillary tube 150 in the two-phase state during the coolingoperation. On the other hand, the length L2 may be set so that therefrigerant flows into the second capillary tube 150 in the single phasestate and then flows into the first capillary tube 110 in the two-phasestate during the heating operation.

The conversion between the single phase flow and the two-phase flow maybe unclear at the connection part 130 of the first and second capillarytubes 110 and 150. However, it may be understood that the two-phase flowof the refrigerant may be larger within the first capillary tube 110than the second capillary tube 150 during the cooling operation, and thetwo-phase flow of the refrigerant may be larger within the firstcapillary tube 110 than the second capillary tube 150 during the heatingoperation.

FIG. 4 is a graph illustrating a difference in a flow rate of arefrigerant in cooling and heating operations according to anembodiment. Hereinafter, a flow rate difference of the refrigerantduring the cooling and heating operation according to an embodiment willbe described with reference to FIG. 4.

Referring to FIG. 4, a horizontal-axis variable of the graph representsD2/D1 (an inner diameter of the second capillary tube to an innerdiameter of the first capillary tube), and a vertical-axis variablerepresents a directional refrigerant flow rate difference (hereinafter,referred to as a “refrigerant flow rate difference”).

Since D2 may be greater that D1, a valve of D2/D1 may exceed 1. Also,the more the value of D2/D1 increases, the more the refrigerant flowrate difference may increase. Also, the value of D2/D1 may be less than5.

For example, when the D2/D1 is 1.14, the refrigerant flow ratedifference may be about 3.2%. That is, the refrigerant flow rate in thecooling operation mode may be greater by about 3.2% than that in theheating operation mode. For example, when the refrigerant flow rate inthe heating operation mode is about 100, the refrigerant flow rate inthe cooling operation mode may be about 103.2.

Also, when D2/D1 is about 1.32, the refrigerant flow rate difference maybe about 13%. As shown in FIG. 4, the plurality of capillary tubes mayhave inner diameters different from each other to secure a greaterrefrigerant flow rate in the cooling operation mode than in the heatingoperation mode.

Hereinafter, another embodiment will be described with reference to FIG.5. In describing this embodiment, like reference numerals have been usedto indicate like elements, and repetitive description has been omitted.

FIG. 5 is a view illustrating a portion of an expander according toanother embodiment. Referring to FIG. 5, an expander 100 according tothis embodiment may include a first capillary tube 110 connected to anoutlet side of an outdoor heat-exchanger 30, a second capillary tube 150connected to an outlet side of an indoor heat-exchanger 40, and aconnection member 140 disposed between the first capillary tube 110 andthe second capillary tube 150.

The connection member 140 may be a tank, in which refrigerant may betemporarily received while flowing into the expander 100. The connectionmember 140 may connect the first capillary tube 110 to the secondcapillary tube 150.

The connection member 140 may include a first connection portion 141connected to the first capillary tube 110 and a second connectionportion 142 connected to the second capillary tube 150. The firstconnection portion 141 may be disposed at one side of the connectionmember 140, and the second connection portion 142 may be disposed at another side of the connection member 140. The refrigerant within thefirst and second capillary tubes 110 and 150 may flow into theconnection member 140 through the first and second connection portions141 and 142.

An inner diameter D3 of the connection member 140 may be greater thaneach of an inner diameter D1 of the first capillary tube 110 and aninner diameter D2 of the second capillary tube 150. That is, arefrigerant flow sectional area of the connection member 140 may begreater than that of each of the first and second capillary tubes 110and 150.

Because the connection member 140 has an inner diameter or sectionalarea greater than that of each of the first and second capillary tubes110 and 150, a decompression effect while the refrigerant flows into theconnection member 140 may not be large. Thus, when the refrigerant isdirectly introduced from the first capillary tube 110 into the secondcapillary tube 150 or from the second capillary tube 150 into the firstcapillary tube 150 like the foregoing embodiment, refrigerantdecompression and refrigerant flow rate adjustment effects when therefrigerant is introduced through the connection member 140 may besimilar to those of the foregoing embodiment.

In the cooling operation mode, the refrigerant may flow into theconnection member 140 or the second capillary tube 150 in a two-phasestate. Also, in the heating operation mode, the refrigerant may flowinto the connection member 140 or the first capillary tube 110 in thetwo-phase state.

Also, as shown in the embodiments disclosed herein, a refrigerant flowrate in the cooling operation mode may be greater than that in theheating operation mode. Thus, the refrigerant flow rate required for thecooling or heating operation mode of the system may be satisfied.

According to embodiments disclosed herein, the flow rate of therefrigerant flowing according to the operation direction of the airconditioner may be adequately controlled to improve the cooling orheating performance.

Also, the refrigerant passing through the condenser when the coolingoperation is performed may flow into the capillary tube having arelatively small inner diameter in the single phase state and flow intothe capillary tube having a relatively large inner diameter in thetwo-phase state. Thus, the flow resistance may be reduced to secure thehigh refrigerant flow rate.

On the other hand, the refrigerant passing through the condenser whenthe heating operation is performed may flow into the capillary tubehaving a relatively large inner diameter in the single phase state andflow into the capillary tube having a relatively small inner diameter inthe two-phase state. Thus, the flow resistance may relatively increaseto reduce the refrigerant flow rate.

Also, since the refrigerant may adequately flow according to theoperation modes, that is, the cooling mode or the heating mode, therefrigeration cycle may be economically performed.

Also, since the plurality of capillary tubs may be connected to eachother in series to constitute the expander, the system may be simplifiedin structure and inexpensive in manufacturing costs.

According to embodiments disclosed herein, the flow rate of therefrigerant flowing according to the operation direction of the airconditioner may be adequately controlled to improve the cooling orheating performance. Thus, industrial applicability may be significantlyimproved.

Embodiments disclosed herein provide an air conditioner in which aplurality of expanders are disposed in series.

Embodiments disclosed herein provide an air conditioner that may includea compressor that compresses a refrigerant; an outdoor thatheat-exchanges heat-exchanging with the refrigerant discharged from thecompressor according to a first operation mode; an indoor heat-exchangerthat heat-exchanges with the refrigerant discharged from the compressoraccording to a second operation mode; and an expander that decompressesthe refrigerant passing through the outdoor heat-exchanger or the indoorheat-exchanger. The expander may include a first decompression part orportion disposed at an outlet side or an inlet side of the outdoorheat-exchanger, the first decompression part or portion having a firstinner diameter, and a second decompression part or portion connected tothe first decompression part in series, the second decompression part orportion having a second inner diameter greater than the first innerdiameter.

Embodiments disclosed herein further provide an air conditioner that mayinclude a compressor that compresses a refrigerant; an outdoorheat-exchanger disposed in an outdoor space that condenses therefrigerant passing through the compressor in a cooling operationprocess; an indoor heat-exchanger disposed in an indoor space tocondense the refrigerant passing through the compressor in a heatingoperation process; and a plurality of capillary tubes that expand therefrigerant introduced through the indoor heat-exchanger or the outdoorheat-exchanger, the plurality of capillary tubes being connected to eachother in series. In the cooling or heating operation process, therefrigerant passes through the plurality of capillary tubes.

Embodiments disclosed herein additionally provide an air conditionerhaving a refrigeration cycle constituted by sequentially connecting acompressor, an outdoor heat-exchanger, an expander, and an indoorheat-exchanger to each other that may include a flow conversion part orconverter that guides a refrigerant discharged from the compressor intothe outdoor heat-exchanger or the indoor heat-exchanger. The expandermay include a first capillary tube disposed between the outdoorheat-exchanger and the indoor heat-exchanger, the first capillary tubehaving a first inner diameter, and a second capillary tube coupled to anend of one side of the first capillary tube, the second capillary tubehaving a second inner diameter greater than the first inner diameter.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. An air conditioner, comprising: a compressor that compresses arefrigerant; an outdoor heat-exchanger that heat-exchanges with therefrigerant discharged from the compressor according to a firstoperation mode; an indoor heat-exchanger that heat-exchanges with therefrigerant discharged from the compressor according to a secondoperation mode; and an expander that decompresses the refrigerant havingpassed through the outdoor heat-exchanger or the indoor heat-exchanger,wherein the expander comprises: a first decompression portion disposedat an outlet side or an inlet side of the outdoor heat-exchanger, thefirst decompression portion having a first inner diameter; and a seconddecompression portion connected to the first decompression portion inseries, the second decompression portion having a second inner diametergreater than the first inner diameter.
 2. The air conditioner accordingto claim 1, wherein, in the first operation mode, the refrigerant isintroduced into the second decompression portion through the firstdecompression portion.
 3. The air conditioner according to claim 1,wherein, in the second operation mode, the refrigerant is introducedinto the first decompression portion through the second decompressionportion.
 4. The air conditioner according to claim 1, wherein, in thefirst operation mode, the first decompression portion is disposed at theoutlet side of the outdoor heat-exchanger, and the second decompressionportion is disposed at an inlet side of the indoor heat-exchanger. 5.The air conditioner according to claim 1, wherein, in the secondoperation mode, the first decompression portion is disposed at the inletside of the outdoor heat-exchanger, and the second decompression portionis disposed at an outlet side of the indoor heat-exchanger.
 6. The airconditioner according to claim 1, wherein the first decompressionportion comprises: a cooling refrigerant inflow portion, through whichthe refrigerant discharged from the outdoor heat-exchanger isintroduced, or refrigerant having passed through the seconddecompression portion is discharged; and a first coupling portioncoupled to the second decompression portion.
 7. The air conditioneraccording to claim 1, wherein the second decompression portioncomprises: a heating refrigerant inflow portion, through which therefrigerant discharged from the indoor heat-exchanger is introduced, orrefrigerant having passed through the first decompression portion isdischarged; and a second coupling portion coupled to the firstdecompression portion.
 8. The air conditioner according to claim 1,wherein an end of the first decompression portion is coupled to an endof the second decompression portion.
 9. The air conditioner according toclaim 1, further comprising a connection member disposed between thefirst decompression portion and the second decompression portion thatconnects the first decompression portion to the second decompressionportion.
 10. The air conditioner according to claim 9, wherein theconnection member comprises a tank that connects the first decompressionportion to the second decompression portion.
 11. The air conditioneraccording to claim 1, wherein the first operation mode is a coolingoperation mode, and the second operation mode is a heating operationmode.
 12. The air conditioner according to claim 1, wherein a ratio ofthe second inner diameter to the first diameter is greater than about 1and less than about
 5. 13. An air conditioner, comprising: a compressorthat compresses a refrigerant; an outdoor heat-exchanger disposed in anoutdoor space that condenses the refrigerant having passed through thecompressor in a cooling operation mode; an indoor heat-exchangerdisposed in an indoor space that condenses the refrigerant having passedthrough the compressor in a heating operation mode; and a plurality ofcapillary tubes that expands the refrigerant introduced through theindoor heat-exchanger or the outdoor heat-exchanger, the plurality ofcapillary tubes being connected to each other in series, wherein, in thecooling or heating operation mode, the refrigerant passes through theplurality of capillary tubes.
 14. The air conditioner according to claim13, wherein the plurality of capillary tubes comprises: a firstcapillary tube having a first diameter; and a second capillary tubehaving a second diameter greater than the first diameter of the firstcapillary tube.
 15. The air conditioner according to claim 14, wherein,in the cooling operation mode, the refrigerant passes through the firstcapillary tube and then passes through the second capillary tube. 16.The air conditioner according to claim 15, wherein the refrigerant flowsinto the second capillary tube in a two-phase state.
 17. The airconditioner according to claim 14, wherein, in the heating operationmode, the refrigerant passes through the second capillary tube and thenpasses through the first capillary tube.
 18. The air conditioneraccording to claim 17, wherein the refrigerant flows into the firstcapillary tube in a two-phase state.
 19. The air conditioner accordingto claim 14, wherein a ratio of the second inner diameter to the firstinner diameter is greater than about 1 and less than about 5
 20. An airconditioner having a refrigeration cycle formed by a compressor, anoutdoor heat-exchanger, an expander, and an indoor heat-exchangerconnected to each other in series, the air conditioner comprising: aflow converter that guides a refrigerant discharged from the compressorinto the outdoor heat-exchanger or the indoor heat-exchanger; and theexpander, wherein the expander comprises: a first capillary tubedisposed between the outdoor heat-exchanger and the indoorheat-exchanger, the first capillary tube having a first inner diameter;and a second capillary tube coupled the first capillary tube, the secondcapillary tube having a second inner diameter greater than the firstinner diameter.
 21. The air conditioner according to claim 20, wherein,when the refrigeration cycle performs a cooling operation, therefrigerant passes through the first capillary tube and then passesthrough the second capillary tube.
 22. The air conditioner according toclaim 20, wherein, when the refrigeration cycle performs a heatingoperation, the refrigerant passes through the second capillary tube andthen passes through the first capillary tube.
 23. The air conditioneraccording to claim 20, wherein one end of the second capillary tube iscoupled to one end of the first capillary tube.
 24. The air conditioneraccording to claim 23, further comprising a connection member thatconnects the one end of the second capillary tube to the one end of thefirst capillary tube.
 25. The air conditioner according to claim 24,wherein the connection member comprises a tank that connects the firstcapillary tube to the second capillary tube.
 26. The air conditioneraccording to claim 17, wherein a ratio of the second inner diameter tothe first inner diameter is greater than about 1 and less than about 5.27. An expander for an air conditioner, the expander comprising: a firstdecompression portion having a first inner diameter; and a seconddecompression portion connected to the first decompression portion andhaving a second inner diameter greater than the first inner diameter,wherein a flow rate of refrigerant through the expander increases ordecreases based on a direction of refrigerant flow.
 28. The expanderaccording to claim 27, wherein a ratio of the second inner diameter tothe first inner diameter is greater than about 1 and less than about 5.29. The expander according to claim 27, wherein the first decompressionportion comprises a first capillary tube and the second decompressionportion comprises a second capillary tube connected to the firstcapillary tube.
 30. An air conditioner comprising the expander of claim27.